Cestodes

Question 1

What is the agent of Cysticercosis?

Answer 1

Taenia solium

Question 2

What is the causative agent of fish tapeworm?

Answer 2

Diphyllobothrium latum

Question 3

Which tapeworm is characterized by its wide proglottids and rosette shaped uterus?

Answer 3

Diphyllobothrium latum

Question 4

Name a tapeworm that grows to remarkable lengths – up to 60 feet long.

Answer 4

Diphyllobothrium latum

Question 5

The scolex of this tapeworm is described as having two leaf-shaped suckers.

Answer 5

Diphyllobothrium latum

Question 6

Exhaustion of vitamin B12 is possible over many years, resulting in megaloblastic anemia. This occurs in less than 2% of patients. Name the tapeworm associated with this condition.

Answer 6

Diphyllobothrium latum

Question 7

Name the drug used to treat Diphyllobothrium latum.

Answer 7

Praziquantel

Question 8

Name the causative agent of beef tapeworm.

Answer 8

Taenia saginata

Question 9

This tapeworm produces mature proglottids with greater than 13 lateral branches in the uterus.

Answer 9

Taenia saginata

Question 10

This species of Taenia has a scolex characterized by having 4 suckers, and no hooklets.

Answer 10

Taenia saginata

Question 11

Eggs produced by this species of Taenia will NOT hatch in the human intestine.

Answer 11

Taenia saginata

Question 12

This species of Taenia can have 1000 – 2000 proglottids, each producing up to 100,000 eggs.

Answer 12

Taenia saginata

Question 13

This species of Taenia can have an average of 1000 proglottids, each producing up to 50,000 eggs.

Answer 13

Taenia solium

Question 14

Eggs of this species of Taenia WILL hatch in the human intestine. The oncosphere from this egg will penetrate the intestinal wall, migrate to soft tissues including the brain.

Answer 14

Taenia solium

Question 15

The leading cause of epilepsy in children in Los Angeles county.

Answer 15

Neurocysticercosis caused by Taenia solium.

Question 16

Name the drug of choice for treatment of Taenia infections.

Answer 16

Praziquantel.

Question 17

The scolex of this species of Taenia is characterized by having 4 suckers and a row of hooklets that are used to attach to the intestine.

Answer 17

Taenia solium

Question 18

Mature proglottids of this species of Taenia are characterized by having less than 13 lateral branches of it’s uterus.

Answer 18

Taenia solium

Question 19

Name the causative agent of dog tapeworm.

Answer 19

Dipylidium caninum

Question 20

Humans acquire this tapeworm infection by ingesting arthropods (often fleas) which contain the cysticercoid.

Answer 20

Dipylidium caninum

Question 21

Proglottids of this tapeworm separate from the strobila and can migrate out of the anus. Clinicians might encounter an anxious mother who reports finding “rice grain or cucumber seed sized worms” in her childs diaper.

Answer 21

Dipylidium caninum

Question 22

This tapeworm produces egg packets containing embryonated eggs that are ingested by arthropods.

Answer 22

Dipylidium caninum

Question 23

The intermediate host of this tapeworm is an arthropod that ingests the eggs, which hatch an onchosphere, which migrates to the body cavity of the arthropod and develops into a cysticercoid larvae.

Answer 23

Dipylidium caninum

Question 24

Name the treatment of choice for Dipylidium caninum

Answer 24

Praziquantel

Question 25

This small tapeworm has only three proglottids, lives in the intestine of canines, and is responsible for formation of hydatid cysts in humans.

Answer 25

Echinococcus granulosus

Question 26

Dogs are infected with this tapeworm when they eat infected intermediate hosts, usually sheep, goat, swine, cattle etc.

Answer 26

Echinococcus granulosus

Question 27

This tapeworm infection may first be noticed as a large space-occupying lesion on an xray or other image.

Answer 27

Echinococcus granulosus

Question 28

These tapeworms are acquired by the accidental ingestion of rodent droppings containing infective eggs.

Answer 28

Hymenolepsis diminuta and Hymenolepis nana. Both cause mild symptoms (unless heavily infected). These are primarily parasites of children.

Question 29

Infection with this cestode may first be detected as a “bulls eye” lesion on x-ray.

Answer 29

Taenia solium

Question 30

Infection with this cestode is acquired by eating raw or poorly cooked fish containing plerocercoid larvae.

Answer 30

Diphyllobothrium latum

Question 31

Embryonated eggs of this cestode release a coracidium which is eaten by crustaceans. There they develop to a procercoid larvae.

Answer 31

Diphyllobothrium latum

Question 32

This term is synonymous with plerocercoid larvae. This term is often used to desribe infection with which cestode? What is the synonymous term?

Answer 32

Diphyllobothrium latum Plerocercoid larva is called a sparganum. Infection is called sparganosis.

Question 33

How do children acquire infection with dog tapeworm?

Answer 33

They ingest fleas containing the cysticercoid.

Question 34

What behavior might the family dog exhibit if infected with dog tapeworm?

Answer 34

Dogs may scrape their anal region across grass or carpet to relieve itching.

Question 35

Infection with this cestode features production of protoscoleces inside a fluid filled cyst.

Answer 35

Echinococcus granulosus

Question 36

True/False: Fluid from a hydatid cyst is highly toxic and can cause anaphylactic shock if the cyst ruptures.

Answer 36

TRUE

Question 37

Detection of this cestode might occur during routine x-ray for other purposes. Examination of the image would reveal a large space-occupying lesion.

Answer 37

Echinococcus granulosus

Question 38

The definitive hosts of these cestodes are rodents.

Answer 38

Hymenolepis diminuta and Hymenolepis nana

Question 39

True/False: Humans are accidentally infected with Hymenolepis diminuta by the accidental ingestion of rodent feces.

Answer 39

False. Humans are infected with Hymenolepis diminuta by ingestion of an insect harboring the cysticercoid larvae.

Question 40

True/False: Eggs of Hymenolepis diminuta are distinguished from eggs of Hymenolepis nana by the presence of polar filaments in the H. nana egg.

Answer 40

True. Some refer to their grandmother as “nana”. Picture your grandmother (nana) with polar filaments or a mustache!

Question 41

Humans can acquire this rodent tapeworm either by ingestion of insescts containing cysticercoid larvae or direct ingestion of embryonated eggs in contaminated food or water.

Answer 41

Hymenolepis nana

Question 42

Which Taenia is characterized as having an “armed” rostellum?

Answer 42

Taenia solium

Question 43

An anxious mother brings her baby to you and describes small motile seed-like white “things” in the child’s diaper. What item might you add to your differential diagnosis from this information? What question(s) might you ask the mother to help verify your suspicions? What would be a good test to order?

Answer 43

Dipylidium caninum might be the cause. You could ask if there is a dog in the family. Request a stool from the child and examination for O&P .

Question 44

You examine tapeworm segments passed by a patient, and notice that the segments are wider than they are long. Whih species does this suggest to you?

Answer 44

Diphyllobothrium latum

Question 45

Name parasitic infections (genus and species) I might acquire by eating raw or poorly cooked pork.

Answer 45

Taenia solium Trichinella spiralis Cysticercosis (larval form of Taenia solium)

Question 46

Name parasitic infection(s) genus and species) I might acquire by eating raw or poorly cooked beef.

Answer 46

Taenia saginata.

Question 47

What is the genus and species of the dwarf tapeworm?

Answer 47

Hymenolepis nana